In this tutorial we set up a process model for the milling of iron ore in a closed circuit.
The process consists of a mill, a feed tank, a sump tank and a hydrocyclone.
The tutorial demonstrates:
- The use of partition curves
- The setting of milling parameters
- The modelling mineral process circuits based on individual mineral performance
You will go through the following steps in order tocomplete the tutorial:
- Draw the flowsheet
- Set up feed components and flowrates
- Set up the feed distribution
- Set the milling parameters
- Setup the hydrocyclone parameters
- Add a unit designer to constrain percentage solids
- Calculate and examine the results
The first step is to draw the flowsheet. Add a mill, a feed tank (by adding a tank and then in the properties viewer under equipment, change the agitation equipment to “none”), a sump tank (by adding a tank and then in the properties viewer under equipment, change the agitation equipment to “none” and then change the bottom, under equipment, to “pumpbox) and a hydrocyclone to the Page Viewer and connect them in the way shown in Figure 1.
Figure 1. The closed milling circuit.
Add the components to the project and set the “Feed” flow rates as shown in Table 1.
Table 1. Feed composition to the milling circuit.
Set the flow of water in the "water" stream to 1 t/hr.
Now we wish to specify separate size distributions for the iron and the silica. Following the same procedure as described in the tutorial 8 (Steps 7 and 8).
Go to the stream manager and the check boxes for Fe and SiO2 as shown in Figure 2.
Figure 2. Select Components that will have a size distribution.
Once these have been selected, go to the “DistributionSheetAndChart” tab. You will see a line for Fe and for SiO2. Under the “Size” column where it says “micron” click on the ellipsis (“...”).
In the window that pops up fill in the parameters as shown in Figure 3. Do this for both Fe and SiO2. You have now defined the domain for the size distributions for Fe and SiO2.
Now you can define the actual size distributions for each. Select the ellipsis for Fe and fill in the parameters so that they are the same as in Figure 4. Do the same for SiO2. Once you have completed accepting these parameters you will see that there are now values in the size distribution column for the iron and silica for the FEED stream.
Figure 3. Define FEED size classes for Fe and SiO2.
Figure 4. The particle size distribution form for Fe and SiO2.
Select and edit the mill properties as shown in Figure 5.
Figure 5. Milling properties.
Select "Parameters" in the Properties Viewer and then press the ellipsis button. This will launch the milling parameters form.
Select the Fe(s) component and add the parameter values shown in Figure 6.
Figure 6. Milling parameters for Fe (s).
Select SiO2(s) and add the parameter values shown in Figure 7.
Figure 7. Milling parameters for SiO2 (s).
Once the values are inputted for both iron and silica, click “Apply” then “OK”.
Note: Ignore the parameter values shown for water (H2O)
Select the Hydrocyclone and edit the values of the properties so that they are the same as those shown in Figure 8.
Figure 8. Hydrocyclone properties.
Select "Parameters" in the Properties Viewer and then press the ellipsis button (…). This will launch the hydrocyclone partition curves parameters form.
Select the Fe(s) component and then add the parameter values shown in Figure 9.
Figure 9. Partition function for Fe (s).
Select SiO2 (s) and add the parameter values shown in Figure 10.
Figure 10. Partition function for SiO2 (s).
Add a Unit Designer to the project. The purpose of the Unit Designer is to control the percentage solids entering the hydrocyclone.
This is achieved by changing the amount of water added to the hydrocyclone feed tank.
Link it to the Hydrocyclone feed tank by editing the ProcessUnitID property.
Link the measurement and design functions to the hydrocyclone feed stream and the water makeup stream, respectively.
Select the measurement variable in the Property Viewer. Change the measurement variable to "Solids" and set the required value to 30%.
Change the minimum and maximum flows for the designer to 0.001 and 3 t/hr, respectively.
The values of the properties for the Unit Designer should be similar to those shown in Figure 11.
Figure 11. Property values for the Unit Designer.
Run the project.
In the “Distributions” tab, select the feed (stream 101) and product (stream 107) distributions(the check-boxes).
You should get results similar to those shown in Figure 12.
Figure 12. Size distributions for the hydrocyclone circuit.
In both graphs presented in Figure 12, the product stream distribution is the top curve while the feed stream is the bottom curve.